<template>
    <div>
        <router-link tag="div" class="header-abs" to="/" v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>

<script>
export default {
    name:'DetailHeader',
    data(){
        return{
            showAbs:true,
            opacityStyle:{
                opacity:0
            }
        }
    },
    methods:{
        handleScroll(){
            const top =document.documentElement.scrollTop
            if (top > 60){
                let opacity =top/140
                opacity=opacity>1? 1:opacity
                this.opacityStyle={
                    opacity:opacity
                }
                this.showAbs=false
            }else{
                this.showAbs=true
            }
        }
    },
    mounted(){
        window.addEventListener('scroll',this.handleScroll)
    },
    destroyed () {
        window.removeEventListener('scroll', this.doScroll)
    }
}
</script>

<style lang="stylus" scoped>
    @import '~styles/varibles.styl'
    .header-abs
        position:absolute
        left:.2rem
        top:.2rem
        width:.8rem
        height:.8rem
        line-height:.8rem
        text-align:center
        border-radius:.4rem
        background:rgba(0,0,0,0.8)
        .header-abs-back
            color:#fff
            font-size:.4rem
    .header-fixed
        z-index:2
        position:fixed
        top:0
        left:0
        right:0
        height: 0.907rem
        overflow:hidden
        line-height: 1rem
        text-align:center
        color:#fff
        background:$bgColor
        font-size:.32rem
        .header-fixed-back
            position absolute
            width:.64rem
            top:0
            left:0
            font-size:.4rem
            text-align center
            color:#fff
            line-height: .9rem
</style>